b. falahatkar

Despite studies on the effect of androgens in female teleost fish, many aspects of androgen supplementation in female sturgeon gametogenesis remain elusive. The aim of the study was to investigate the immunological and physiological responses of 4-year-old previtellogenic great sturgeon (Huso huso) (body weight 5580±165 g) to 11-ketotestosterone (11-KT) implants. The fish were divided into two groups of 6 fish: 11-KT group, which received a single intraperitoneal implant of 2.5 mg 11-KT and a placebo group, which was implanted without 11-KT for 56 days. Just before implantation and on days 21 and 56 post-implantation, serum samples were taken to measure immune parameters (IgM, C3 and C4) and some related biochemical and hematological indices. Results showed a significant reduction in IgM concentrations after implantation in both the 11-KT and placebo groups (p<0.05). The concentration of C4 showed an opposite trend and significantly increased in both the placebo and 11-KT groups (p<0.05). The concentration of C3 and IgM to protein (IgM/p) ratio showed no significant differences during the experiment (p>0.05). Serum testosterone (T) levels in the 11-KT implanted group increased significantly on days 21 and 56 post-implantation (p<0.01). The albumin to globulin ratio showed no significant change in the 11-KT group (p>0.05), but a significant difference was observed in the placebo group during the study period (p<0.05). In hematological parameters, the number of red blood cells significantly increased after 56 days compared with that after 21 days in both experimental groups (p<0.05), while white blood cells significantly increased in the 11-KT group after 56 days (p<0.05). The results indicated that implantation with or without 11-KT could suppress some immunity parameters of great sturgeon.

A 60-day trial with six diets (three different protein levels × two different lipid levels) containing 30, 35 and 40% protein with 10 and 15% lipid levels was conducted to determine the optimum dietary protein to lipid ratio and effects on growth performance and hematological indices of Aspikutum, Leuciscus aspius female×Rutilus frisii male. Two hundred and fifty two fish (31.2±0.4 g; mean±SEM) were distributed in 18 circular concrete tanks (400 L) and were fed 3 times daily according to their apparent satiation. The results showed that the highest growth rate was achieved when fish fed with diet containing 35% protein and 15% lipid. Lipid productive value was significantly decreased with increasing dietary lipid level. Number of red blood cells, white blood cells, hemoglobin concentration, hematocrit value, mean corpuscular volume, mean corpuscular hemoglobin, neutrophil and eosinophil were not considerably differing among rearing treatments, while mean corpuscular hemoglobin concentration was significantly higher in fish fed with diet containing 30% protein and 10% lipid. The percentage of lymphocyte increased with increasing dietary lipid level, whereas a decrease of monocyte percentage was observed with increasing of dietary lipid level. Dietary protein and lipid level, as well as the interaction showed no significant differences in total lipid, triglyceride, cholesterol and total protein levels. In general, this study has indicated that diet containing 35% protein and 15% lipid had positive effects on growth performance, while no effects on biochemical and hematological parameters was achieved.

Injection of gonadotropin-releasing hormone analogues (GnRHs) produces luteinizing hormone (LH) from pituitary that stimulates gonadal maturation. In female fish, these analogues drive the final oocyte maturation, ovulation and finally spawning. Traditionally, they have been injected either intramuscularly or intraperitoneally. Depending on GnRH type, fish species and water temperature, one-step administration causes the peak of LH within 12-72 hours. In some fishes, this short-time effect of injection is enough for spawning during 2-3 days following the injection. However, asynchronous fishes need more injections but, multiple hormone injections are stressful and harmful and in the long-term, they inhibit reproduction. Therefore, sustained-release delivery systems can be used. A single application of GnRHa-delivery system enters GnRHa into the blood stream continuously, resulting pituitary stimulation for releasing LH that may take several weeks. Therefore, in delivery system, multiple injections can be replaced by single injection. There are different delivery systems includes: cholesterol pellets, ethylene-vinyl acetate implants, and biodegradable microspheres. This paper discusses the methods of hormonal implantation and possibility of its application in some Iranian fishes.

Temperature is the main environmental factor affecting the development of fish eggs. In this study, the effect of incubation temperature on fertilization rate, hatching rate and growth in goldfish (Carassius auratus) was investigated. Egg and sperm production were obtained by ovaprim injection and artificial propagation. Eggs were incubated at four temperatures (21, 24, 27 and 30 °C) with 3 replicates for each treatment and cultured for 40 days at the same temperature. The larvae were grown in the same aquarium that had been hatched under the same temperature condition for 40 days. The results showed that there was no significant difference in fertilization rate of incubated eggs at different temperatures, but the highest (97%) and lowest (94%) fertilization rates were observed at 24 °C and 21 °C, respectively. The maximum incubation time was recorded at 21 °C and the minimum time required at 30 °C (P < 0.05). The highest percentage of hatching (74.4%) was observed at 24 °C and it decreased with increasing water temperature (P < 0.05). Although, the temperature of 30 °C showed the highest value of length, weight and specific growth rate of larvae in comparison to other temperature treatments, but the highest anomalies (13%) were observed in this treatment, too. The best temperature of incubation and growth of larvae is 24°C and 27°C for goldfish, respectively.

A feeding trial with three protein levels (30, 35 and 40%) was conducted to evaluate the effect of dietary protein level on growth performance and hematological parameters of juveniles Beluga sturgeon (Huso huso). One hundred and thirty-five fish (131.71 ± 1.68 g mean ± SD) were randomly distributed in nine circular concrete tanks (800 L) and were satiated four times daily for 8 weeks. The results showed that growth parameters including final weight, specific growth rate, feed conversion ratio, condition factor and weight gain was significantly higher in fish fed 35% protein compared to 40% (P<0.05), but there was no difference with fish fed 30% protein (P>0.05). Weight increased with increasing dietary protein level up to 40%, and then decreased significantly and body weight increase decreased by 40% protein s. The results of hematological parameters showed white blood cells, neutrophils and lymphocytes in fish that fed 35% protein compared to other groups (P<0.05). In conclusion, the results showed that protein restriction have effect on growth performance and hematological parameters of juveniles Beluga sturgeon.

A feeding trial with three protein levels (30, 35 and 40%) and three lipid levels (10, 12 and 14%) was conducted to evaluate the optimum protein and lipid ratio of Caspian Kutum (Rutilus frisii kutum). Six hundred and seventy five fish (1.15±0.01g mean ±SD) were randomly distributed in 27 aquaria (45L) and were fed four times daily for 8 weeks. Results showed that interaction between protein and lipid did not significantly affect the growth parameters. Weight increased with increasing dietary protein level up to 35%, and then decreased significantly. Specific growth rate (SGR) and average daily growth (ADG) of fish fed the diets containing 35 and 40% protein increased with increasing lipid level, but protein efficiency ratio (PER) of fish decreased with increasing dietary protein level. Fish fed the diet containing 40% protein and 10% lipid showed the lower protein productive value (PPV). Lipid efficiency ratio (LER) of fish fed the diets containing 30 and 35% protein decreased significantly with increasing lipid level (p< 0.05). Lipid production value (LPV) of fish fed the 35% protein and 10% lipid was higher than those of other treatments. Results regarding to the analysis of body compositions showed that dietary protein levels made no significant differences among treatments, but the increase of lipid level in diets led to fish body lipid increase and the highest amount of lipid were observed in fingerlings fed 35% protein and 14% lipid. Survival was 100% in all treatment. In conclusion, it appears that Caspian Kutum juveniles could adapt to 14% dietary lipid without negative effects on growth and the diet containing 35% protein with 14% lipid would be suitable for optimum growth of Caspian.

This experiment was carried out to investigate the effect of different levels of dietary lactoferrin on growth performance and innate immune response of juvenile Siberian sturgeon (Acipenser baeri). Fish (26. 3 ± 0. 2 g) were fed with six different dietary lactoferrin including 0، 100، 200، 400، 800 and 1600 mg/kg for 8 weeks. Growth performance was measured at each 2-week interval. After the feeding trail، blood and mucus samples were collected for estimating hematological and immunological parameters. There was no significant difference between treatments in terms of growth performance (weight gain، specific growth rate، feed conversion ratio، condition factor and hepatosomatic index)، during and at the termination of the experiment (P>0. 05). White blood cell counts (WBC) and differential WBC count were not affected by dietary supplementation of bovine lactoferrin (P>0. 05). Mucus and serum lysozyme activities were not significantly influenced by dietary lactoferrin (P>0. 05). Moreover، mucus secretion significantly increased in fish fed 400 mg/kg lactoferrin compared to control group (P<0. 05). In spite of the significant increase of mucus secretion in fish fed dietary lactoferrin، it seems that the possibility of using this ingredient as an immunostimulant for Siberian sturgeon is low، but further studies are needed to find the effect of lactoferrin on other related immunological indices.

This study was carried out to evaluate the effects of dietary carbohydrate levels on growth performance and body composition of juveniles Caspian Kutum (Rutilus frisii kutum). Fish with initial average weight of 0.8±0.2g (±SD) were fed five isoproteic and isenergic formulated diets with different carbohydrate levels including 15, 20, 25, 30 and 35% in triplicate groups, 4 times daily according to their satiation for 10 weeks. Results showed that increasing the level of carbohydrate to 35% significantly increase some growth indices such as final weight (Wf), weight gain (WG), body weight increase (BWI), specific growth rate (SGR) and protein efficiency ratio (PER). In addition, result of body composition analysis showed that the increase in carbohydrate level lead to increase of protein level. So, the highest amount of protein was observed in fingerlings fed with diet containing 35% carbohydrate. In conclusion, the results indicate that increase in carbohydrate levels from 15 to 35% have not any negative effect on growth parameters and therefore, the level of 35% carbohydrate in the diet of 1-2g Caspian Kutum fingerlings can lead to better efficient in protein and desirable growth.

Artemia (Artemia urmiana) was added to diets of Angelfish and various factors: fecundity, fertilization rate, hatching rate and larvae survival rate and interval between continuous spawning and total time for 8 spawning (did you run 8 spawning cycles, this is not clear) for Angelfish. five diets were tested (n=3): a 40% crude protein diet (control); control diet + live Artemia, live Artemia; live  artemia +  unsaturated fatty acid live Artemia + unsaturated fatty acid + 1gr vitamin C. Broodstock Angelfish (18 pair) were kept in a 50 L aquarium (28 ± 1°C, pH 7.5-8.3,  hardness <170ppm). Fish were fed 4 times per day between 7:00 and 23:00.
The average rate of fecundity was 378 eggs, 98.9% fertilization, 97.5% hatching for fish fed the live artemia + fatty acid. The artemia + fatty acid + 0.5 g vitamin C resulted in the highest larvae survival (93.3%) which was significantly higher than the control group (P < 0.05). The shortest period for 8 spawning cycles (43 days, 6 day interval) was for the Artemia + fatty acid + 1 g vitamin C. Feeding live food reduced the time for 8 spawning cycles and increasing fecundity, fertilization rate, hatching rate and larvae survival rate. Adding artemia decreases this time between spawns and would be a useful ingredient for continuous spawning operations and is likely to be economically for broodstock operations because of increased efficiency even though the feed cost would be higher.